What are the drivers of tree growth? Current vegetation models often implicitly assume that tree growth is limited by photosynthesis (the tree carbon source). Recent evidence however suggests that biophysical limitations to cambial cell expansion and division (carbon sink), e.g., cell turgor pressure, can strongly constrain tree growth, even under ample carbon supply, with large implications for carbon cycle modelling. MiCSS aims to study how carbon source and sink limitations to tree growth might interact. To do so the project will leverage a range of data, from cellular-level observations of wood formation to stand-level estimates of photosynthesis and translate acquired insights into a new model of tree growth.